With police vowing to crack down on disorderly conduct, protests over the George Zimmerman acquittal continued in Los Angeles on Tuesday for the fourth day, with demonstrators calling for legal reform and intervention by the federal government in the Florida case.

At least two different demonstrations were held Tuesday night, while a third was canceled for fear of violence. Initial reports from the gatherings at City Hall and Leimert Park were that they were relatively peaceful.

"I'm out here because the underlying tone of this verdict was racism," said Antonio Calley, 41, an African-American man from Los Angeles who was at the City Hall rally holding a sign that read "Your move Eric Holder."

"I think the attorney general can make this right," he added.

More than 150 people attended a demonstration at City Hall organized by an activist group called Coalition L.A. The group marched around the block and in front of police headquarters. By early evening, no arrests had been made, police said.

In Leimert Park, dozens of protesters gathered near the intersection of Crenshaw Boulevard and Vernon Avenue as police passed out fliers warning that criminal conduct such as violence, vandalism and trespassing would be prosecuted.

The events stood in contrast to protests held Monday night and over the weekend, in which individuals in the crowds engaged in rowdy and violent behavior, according to police.

Protesters upset about the Zimmerman verdict will no longer be allowed to march in the streets, as the department has allowed on previous nights, Beck said. Instead, they must stay on the sidewalk.

The new LAPD tactics were announced in the wake of the arrest of some two dozen people amid violent demonstrations along Crenshaw Boulevard and other areas of the city Sunday and Monday nights.

Police declared an unlawful assembly in South Los Angeles shortly before 10 p.m. Monday after a group of about 150 demonstrators grew rowdy and broke off the main crowd, Beck said. The group allegedly committed assault, vandalized businesses, stole merchandise and jumped on cars. The night before, more than 100 protesters entered the eastbound 10 Freeway on-ramp at Crenshaw Boulevard and blocked traffic for about 30 minutes and several people vandalized the W Hotel in Hollywood.

On Tuesday, Beck described the aggressive crowd in Monday night's protest as relatively small and not part of the main group demonstrating against the Zimmerman verdict. He described the group as "leaderless" and "highly mobile" as they walked down Crenshaw Boulevard.

Beck said he supported citizens' right to protest, calling it a "sacred piece of American politics."

"I am very disappointed in those few people that are going to abridge the rights of many," Beck told reporters gathered at the LAPD's downtown headquarters.

Monday was the third night of demonstrations in the area by those angered by a Florida jury's acquittal of Zimmerman, a neighborhood watch volunteer, in the 2012 killing of unarmed black teen Trayvon Martin in Sanford, Fla.

Beck confirmed news reports that the LAPD spotted some troublemakers in the crowd from the 2011 Occupy L.A. rallies, as well as some from the neighborhood. He wouldn't reveal how many officers were deployed for protests Tuesday night but said about 350 police officers were out on Monday night. By contrast, about 1,000 LAPD officers were deployed in 2010 when Lakers fans turned violent downtown following the team's championship win.

A South L.A.-based community activist Tuesday called off a rally in honor of Trayvon Martin and urged others to do the same in light of the vandalism and violence committed by some of those who have been demonstrating.

Najee Ali, founder of Project Islamic Hope, said his group canceled a rally that was set for 6 p.m. Wednesday in Leimert Plaza Park "in the interest of safety."

"There's no way we can guarantee public safety because the demonstrations have been infiltrated by anarchists and agent provocateurs, whose only goal is to create vandalism, property damage and violence in our community," Ali said by phone Tuesday. "If you have a Trayvon Martin rally or march, you can't stop other members of the public from joining it, disrupting it and causing damage. The emotions are still too high right now."

On Tuesday, Earl Ofari Hutchinson, president of the Los Angeles Urban Policy Roundtable, said his group organized several "Trayvon Martin peace monitors" that were set to be stationed at Crenshaw Boulevard Tuesday to prevent a reoccurrence of Monday night's violence.

"We're monitoring activities, talking to young people and encouraging people to stay home," Hutchinson said earlier Tuesday. "There are better ways, more constructive ways to get justice for Trayvon Martin and his family."

Fourteen arrests were made during Monday night's protests, one for inciting a riot and 13 for failure to disperse, of which six were juveniles. Ten arrests were made the night before.

Amid the chaos, a KCAL (Channel 9) cameraman was struck from behind Monday night and was taken to the hospital for treatment of a possible concussion, LAPD Lt. Andy Neiman said. As he was hit and swung around, his camera struck his reporter, who was treated at the scene for an injury.

Caitlin Alvarez, 25, of Pasadena said Tuesday that she and a friend were heading back to their car about 9:15 p.m. Monday after protesting when a demonstrator grabbed her friend's purse. When Alvarez tried to help out her friend, she said, someone shoved her against a wall and several people started banging her head against it and punched her in the face and in the chest. Her friend, Ashley Wells, 27, of Monrovia was curled up on the floor in a ball as several people also kicked her several times.

Alvarez said her friend -- who never retrieved her purse -- spent the night in the hospital, while she herself visited a hospital emergency room on Tuesday. Alvarez, who is waiting for X-rays to see if she has a broken nose or rib, tried to report the incident Monday night with officers at the protest but was told she would have to come to the police station, something she said she planned on doing by today.

"I really feel sad that it turned into that," Alvarez said. "We were clearly there in solidarity. We're never going to get any of our demands met because we just look like hooligans without a purpose if we continue to turn on each other."

Neiman said they were investigating reports from that night of damaged businesses and vehicles, some of which were stopped at a light when they were allegedly attacked.

Mayor Eric Garcetti applauded those who peacefully expressed their opinions, which he said was the overwhelming majority of the community members who attended Monday night's prayer vigil in Leimert Plaza Park.

While the trial in Florida has ignited passions, he said Monday night, "We have to make sure that it will not ignite the city."

"People deserve to be able to express their opinions, and we will continue to allow that space to happen, but people also deserve to be safe on their streets and in their cars," he said.

County Supervisor Mark Ridley-Thomas said he plans to revive his "Days of Dialogue" teams formed after the 1992 riots to bring different groups together to discuss the meaning of the Martin case and Zimmerman's acquittal.

He also urged the city to join in the appeal to Attorney General Eric Holder to open a new inquiry into possible civil rights violations.

Garcetti, however, said he wanted to talk with Holder before urging such an action.